Project Summary/Abstract This grant proposal seeks to identify the first known cytoskeleton-specific stress response and the potential regulators of this pathway. Previous work in yeast has identified an age-associated decline in cytoskeletal function and its implications in lifespan, while recent work in C. elegans have identified HSF-1 in mediating a protective role in cytoskeletal integrity. Marrying these findings, we propose to characterize both systemic and tissue-specific cytoskeletal decline as a function of age in the multicellular model organism, C. elegans. Next, we would like to identify the key players working both in synergy or independently of HSF-1 in protecting cytoskeletal integrity under stress and aging. Finally, we can determine whether the cytoskeletal stress response itself declines over age, as many stress response pathways do ? including mitochondrial, endoplasmic reticulum, and cytoplasmic ? and whether ectopic activation can rescue cytoskeletal function in advanced age. We will employ both biochemical and imaging methods to test our hypotheses. We propose to study cytoskeletal function by imaging of actin using LifeAct. In addition, we will purify actin proteins in a tissue- specific manner and study their function in worms at various stages of adulthood. Finally, we propose to perform a candidate screen of 400 transcription factors to identify novel regulators of cytoskeletal function. Here, endocytosis and organization of muscle fibers will be used as a readout for cytoskeletal integrity and function. At the culmination of this study, we will have characterized the cytoskeletal stress response as a function of age. Moving forward, this will open exciting avenues of research in continuing to map out the mechanistic pathway of the cytoskeletal stress response, as well as identifying the conservation of this mechanism in mammals and disease models.